1. Field of the Invention
The present invention relates to a touch panel and a method of forming the same.
2. Description of the Related Art
Due to the popularity of computers, keyboards and optical mice, such devices have become some of the most commonly used data input apparatuses. However, because they are bulky and inconvenient to carry, a touch input device that can be combined with a screen is additionally being developed.
A touch panel can be operated either directly by a finger or by a stylus. A touch panel is a humanized input device that allows contact on a specific area on a panel to input a command The trend of developing light, thin, short and small electronic products with complex functions has resulted in such electronic products having reduced space for housing additional parts; therefore, having a touch panel that occupies less space is suitable. In addition to simultaneously providing the functions of a keyboard and an optical mouse, a touch panel allows handwriting. Therefore, the touch panel is a best choice as a human-machine interface.
According to their operating principles, touch panels can be categorized into resistive, capacitive, optical, and surface acoustic wave types. A resistive type panel has a disadvantage of having low light transmittance; therefore, its brightness and contrast are low. A capacitive panel is easily affected by panel temperature and humidity, and its detection result varies with the ground voltage level; therefore, the capacitive panel has poorer stability. In addition, a capacitive panel cannot have a detection result if a nonconductor is used to operate. The resolution of an optical touch panel is determined by the number of infrared emitters and corresponding receivers applied on the optical touch panel; therefore, the resolution of an optical touch panel is restricted. A surface acoustic wave panel uses a transmit transducer to emit a surface wave and a receive transducer to receive the surface wave, and the surface acoustic wave panel determines a touch location according to the relationship between signal strength and time. U.S. Pat. No. 4,644,100 discloses a surface acoustic wave touch device employing a single transmitting transducer and a single receiving transducer. Since sound waves are quite fast, a high speed signal processor and high performance analog/digital converter is required and results in high cost. However, lowering the cost will compromise the resolution.
The present touch panels still have several disadvantages and require further improvements.